South Korea's nuclear envoy said he had had "constructive" talks with his North Korean counterpart in Bali on the sidelines of the summit of the Association of Southeast Asian Nations.

The face-to-face meeting was the first such contact since six-party talks on North Korea's nuclear program collapsed two years ago.

The July 22 meeting also reportedly was the first time representatives from two countries had held bilateral talks on nuclear issues.

After the meeting, South Korea's Wi Sung-lac said he had "a very constructive and useful conversation" with his counterpart, North Korea's Ri Yong-ho, who was quoted as saying: "We have agreed to make efforts to resume six-party talks as soon as possible."

Tensions have risen between the neighbors since an alleged torpedo attack by the North that sunk a South Korean navy ship, followed by the North's shelling of a South Korean island. The two incidents last year left 50 dead.